The attack on the Plovdiv marshalling yards on 18/19 March (1944), was also spoiled by bad weather, and although some of the illuminators scattered their flares over the area in an effort to locate the yards, no aircraft was definitely able to identify the target

Bombers Over Sand and Snow:205 GroupRAF in World War II
Granfield,Alun
Barnsley:Pen & Sword,2011.
p.251